Screen apparatus

ABSTRACT

This invention provides a screen apparatus having an enhanced capacity for separating foreign matter from fibers of an acceptable quality in paper-making material. The screen apparatus S comprises: a sealed casing  1  having a paper-making material supply port  1   a,  a refined paper-making material discharge port  1   b  positioned above the paper-making material supply port  1   a  and a foreign matter discharge port  1   c  positioned above the refined paper-making material discharge port  1   b ; a screen  2  for dividing the interior of the sealed casing  1  into a first chamber  1 A and a second chamber  1 B and for separating foreign matter in the paper-making material, the screen being of cylindrical shape with end portions both open, the screen having circular holes or slit-like openings on a side face thereof and which screen is stood within the sealed casing  1  in such a way that a direction of height thereof faces a vertical direction;
         a rotor  7  disposed inside the screen  2  within the first chamber  1 A and having an agitating member  7   a  for agitating the paper-making material within the sealed casing  1;  and a water supply passage  10  mounted onto the sealed casing  1  so that a water spouting port  10   a  opposes the top end face  7 T of the rotor  7.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a screen apparatus for refining apaper-making material by feeding it outward of the screen from theinside thereof, and more particularly to a screen apparatus whosecapacity for separating foreign matter from fibers in the paper-makingmaterial that are acceptable in the quality has been enhanced.

2. Description of Related Art

Conventionally, in a so-called “outward type” screen apparatus(centrifugal type) which refines, for example, paper-making material byfeeding it outward of the screen from the inside thereof, a paper-makingmaterial loaded within the screen is agitated by means of an agitatingmember provided on the screen, and then foreign matter in thepaper-making material is removed through the screen so as to refine thepaper-making material (see, for example, patent document 1).

-   Patent document 1: Japanese Patent Application Laid-Open No.    2004-137621 (FIG. 1)

However, in such a “screen apparatus having a cylindrical screen whoseend portions are both open” , no component exists for obstructing theflow of the paper-making material downstream from an end portion atwhich the screen is open, and thus the paper-making material isdischarged out of the casing. Accordingly, from the viewpoint ofenhancing efficiency in separation on the part of the screen there hasbeen room for improvements.

SUMMARY OF THE INVENTION

The present invention sets out to provide a screen apparatus whicheliminates the problem described above.

To achieve the above object,a first aspect of the present inventionprovides a screen apparatus comprising: a sealed casing having apaper-making material supply port, a refined paper-making materialdischarge port positioned above the paper-making material supply portand a foreign matter discharge port positioned above the refinedpaper-making material discharge port; a screen for dividing the interiorof the sealed casing into a first chamber and a second chamber and forseparating foreign matter existing in the paper-making material, thescreen being of a cylindrical shape and with end portions that are bothopen, the screen having circular holes or slit-like openings on a sideface thereof and stood within the sealed casing in such a way that adirection of height thereof faces a vertical direction, both open endportions of the screen having an upper opening portion and a loweropening portion with the upper opening portion positioned below theforeign matter discharge port and the lower opening portion positionedabove the paper-making material supply port; a paper-making materialsupply passage connected to the paper-making material supply port inorder to supply paper-making material to a first chamber from a downwarddirection;a rotor disposed inside the screen within the first chamberand having an agitating member for agitating the paper-making materialwithin the sealed casing; a refined paper-making material dischargepassage connected to the refined paper-making material discharge portand also connected to the second chamber so as to guide paper-makingmaterial that has been refined out of the sealed casing via the screen;a foreign matter discharge passage connected to the foreign matterdischarge port and also connected to the first chamber so as to guideout of the sealed casing foreign matter existing in the paper-makingmaterial and which does not pass through the screen; and a water supplypassage mounted onto the sealed casing so that a water spouting portopposes the top end face of the rotor.

According to a second aspect of the invention, in the first aspect, aring portion provided at a midway position on the screen, the screenbeing divided by the ring portion into an upstream screen portion and adownstream screen portion, the ring portion being provided with adiluted water introduction port for introducing diluted water into thefirst chamber; a diluted water passage provided via the sealed casingand connected to the diluted water introduction port; and an unevenportion provided on a side opposing a rotor of the ring portion, whereina convex portion of the uneven portion is provided so as to project froman inside wall face of the screen, and the uneven portion has a frontend portion of the convex portion and a rear end portion of the convexportion that relative to a vertical direction of the casing ispositioned lower than the front end portion of the convex portion, andwhich front end portion is tilted in such a way that relative to arotational direction of the rotor the front end portion of the convexportion is nearer the rear end portion of the convex portion.

According to a third aspect of the invention, in the first aspect, aring portion provided at a midway position on the screen, the screenbeing divided by the ring portion into an upstream screen portion and adownstream side screen portion, the ring portion being provided with adiluted water introduction port for introducing diluted water into thefirst chamber; a diluted water passage provided via the sealed casingand connected to a diluted water introduction port; and an unevenportion provided on a side opposing a rotor of the ring portion, whereina convex portion of the uneven portion is provided not to project froman inside wall face of the screen and the uneven portion has a front endportion of the convex portion and a rear end portion of the convexportion that relative to a vertical direction of the casing ispositioned lower than the front end portion of the convex portion, andwhich front end portion is tilted in such a way that relative to arotational direction of the rotor the front end portion of the convexportion is located nearer than the rear end portion of the convexportion.

Because the screen apparatus of the first aspect includes a water supplypassage that is mounted on the sealed casing in such a way that a waterspouting port opposes the top end face of the rotor, water collidingwith the top end face of the rotor flows in a substantially horizontaldirection, thereby hampering the flow of a paper-making materialprocessing toward the refined paper-making material discharge port fromthe opening portion at the top of the screen. In other words, thisaction forces back upstream of the first chamber fibers, which wereflowing out to the foreign matter discharge port by reject sealing,thereby enhancing the capacity of the screen apparatus for separatingforeign matter from fibers of an acceptable quality contained in thepaper-making material.

In the screen apparatus of the second aspect, in addition to the effectsof the invention of the first aspect, diluted water from the dilutedwater introduction port acts to hamper the flow of a paper-makingmaterial flowing downstream, thereby enhancing the capacity of thescreen apparatus for separating foreign matter from fibers of anacceptable quality contained in the paper-making material. Further, thepaper-making material passes through the screen upstream and apaper-making material whose density has been intensified is diluted withdiluted water so as to enhance the capacity of the screen apparatus forseparating fibers of an acceptable quality. Further, the convex portionof an uneven portion provided on the side facing the rotor of the ringportion is tilted in such a way that relative to the rotationaldirection of the rotor a front end portion of the convex portion ispositioned closer than the rear end portion of the convex portion.Consequently, pieces in the paper-making material that have not yetmelted and that collide with the convex portion are not only separatedbut also brought back upstream of the paper-making material, therebyfurther enhancing the capacity of the screen apparatus for separatingforeign matter from fibers of an acceptable quality that are containedin the paper-making material.

In the screen apparatus of the third aspect, in addition to the effectsof the invention of the first aspect, diluted water from the dilutedwater introduction port acts to hamper the flow of a paper-makingmaterial flowing downstream, thereby enhancing the capacity of thescreen apparatus for separating foreign matter from fibers of anacceptable quality that are contained in paper-making material. Further,the paper-making material passes through the screen upstream and apaper-making material whose density has been intensified is diluted withdiluted water so as to enhance the capacity of the screen apparatus forseparating fibers of an acceptable quality. Further, the convex portionof the uneven portion provided on the side facing the rotor of the ringportion is tilted in such a way that relative to the rotationaldirection of the rotor a front end portion of the convex portion ispositioned closer than the rear end portion of the convex portion.Consequently, pieces in the paper-making material that have not yetmelted and that collide with the convex portion are not only separatedbut also brought back upstream of the paper-making material, therebyfurther enhancing the capacity of the screen apparatus for separatingforeign matter from fibers of an acceptable quality that are containedin the paper-making material.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic sectional view of a screen apparatus according toan embodiment of the present invention;

FIG. 2 is a schematic sectional view taken along the line 2-2 of FIG. 1;

FIG. 3 is a schematic view of a screen in the vicinity of a ring portionas seen from the inside of the screen;

FIG. 4 is a schematic partially enlarged sectional view showing part ofFIG. 1 in enlargement;

FIG. 5 is a schematic sectional view taken along the line 5-5 of FIG. 4;

FIG. 6 is a schematic sectional view of a screen apparatus according toanother embodiment different from FIG. 1;

FIG. 7 is a schematic plan view of a rotor of FIG. 6;

FIG. 8 is a schematic partially enlarged sectional view showing part ofFIG. 6 in an enlarged form;

FIG. 9 is a schematic partial sectional view of a screen apparatusaccording to another embodiment that is different from FIG. 8;

FIG. 10 is a schematic partial sectional view of a screen apparatusaccording to another embodiment that is different from FIG. 5;

FIG. 11 is a schematic partial sectional view of a screen apparatusaccording to another embodiment that is different from FIG. 4; and

FIG. 12( a) is a schematic sectional view taken along the line 12-12 ofFIG. 11, and FIG. 2( b) is a view of a ring portion of FIG. 12( a) asseen from the inside of the screen.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment of the screen apparatus of the present invention will bedescribed with reference to the accompanying drawings.

With reference to FIGS. 1-5, symbol S denotes a screen apparatus thathas a sealed-type casing 1 including a paper-making material supply port1 a, a refined paper-making material discharge port 1 b located abovethe paper-making material supply port 1 a, a foreign matter dischargeport 1 c located above this refined paper-making material discharge port1 b and a heavy foreign matter discharge port 1 d.

This screen apparatus S is a so-called “outward type” screen apparatus(centrifugal type) which refines a paper-making material by feeding itoutward from inside of the screen 2 in order to remove foreign matter(for example, plastics) contained in the paper-making material (forexample, old newspapers and old corrugated board).

The interior of the sealed-type casing 1 is divided by a screen 2 into afirst chamber 1A and a second chamber 1B.

This screen 2 is intended to separate foreign matter in the paper-makingmaterial. The screen 2 is of a cylindrical shape, its end portions areboth open, its side face has circular holes or slit-like openingportions and it is stood within the sealed casing 1 in such a way thatthe direction of its height faces a vertical direction. Both open endportions of the screen 2 include an upper opening portion 2A and a loweropening portion 2B. As shown in FIG. 1, the upper opening portion 2A islocated below the foreign matter discharge port 1 c and the loweropening portion 2B is located above the paper-making material supplyport 1 a.

Symbol R shown in FIGS. 1-5 denotes a ring portion provided midway onthe screen 2, the screen 2 is divided into an upstream screen portion 21and a downstream screen portion 22 by this ring portion R and the ringportion R has diluted water introduction ports R1 (for example, aplurality of) for purposes of introducing diluted water into the firstchamber 1A.

Reference numeral 20 denotes a diluted water passage for introducingdiluted water, a passage which is connected with the diluted waterintroduction port R1 and is provided via the sealed casing 1. A face ofthe ring portion R that faces the rotor 7 includes convex portions RTthat project from the face of the screen 2 and concave portions RO (seeFIGS. 3, 5).

A convex portion RT provided on a side facing the rotor 7 of the ringportion R in such a way that it projects from the face of the screen 2has a front end portion X of the convex portion and a rear end portion Yof the convex portion that is positioned at a lower position relative tothe vertical direction than the front end portion X of the convexportion, and that is tilted in such a way that relative to therotational direction of the rotor 7 (see the direction of an arrow inFIG. 3) the front end portion X of the convex portion is positionedcloser than the rear end portion Y of the convex portion. Theinclination angle is, for example, 3° and 45°.

As a result, pieces contained in a paper-making material that have notyet melted and that collide with the convex portion RT are not onlyseparated but are also made to return upstream of the paper-makingmaterial, and in consequence the effect of separation between foreignmatter and acceptable fibers in the paper-making material.

The aforementioned convex portion RT and a concave portion RO could alsobe described as an uneven face provided on a side facing the rotor 7 ofthe ring portion R. The convex portion RT of this uneven face isprovided to project from the inner wall face of the screen 2 and has thefront end portion X and a rear end portion Y that is positioned lowerthan the front end portion relative to the vertical direction of thecasing 1. The convex portion RT is tilted in such a way that relative tothe rotational direction (see the direction of arrow in FIG. 3) of therotor 7 the front end portion of the convex portion RT is located nearerthe rear end portion Y of the convex portion RT.

Reference numeral 3 in FIG. 1 denotes a paper-making material supplypassage which is connected to the paper-making material supply port 1 ain order to supply a paper-making material to the first chamber 1A froma downward direction. Reference numeral 4 denotes a refined paper-makingmaterial discharge passage connected to the refined paper-makingmaterial discharge port 1 b in order to guide the refined paper-makingmaterial outside the sealed casing 1 via the screen 2. Reference numeral5 denotes a foreign matter discharge passage that is connected to thefirst chamber 1A and that is also connected to the heavy foreign matterdischarge port 1 c in order to guide foreign matter (for example,relatively light foreign matter) existing in the paper-making materialand which does not pass through the screen 2 outside the sealed casing.Reference numeral 6 denotes a heavy foreign matter discharge passagethat is connected with the first chamber 1A and that is also connectedto the heavy foreign matter discharge port 1 d in order to guiderelatively heavy foreign matter existing in the paper-making materialand which does not pass through the screen 2 outside the sealed casing1.

Reference numeral 7 denotes a rotor, which is disposed inside the screen2 within the first chamber 1A and has on its outer periphery anagitating member 7 a for agitating the paper-making material in thesealed casing 1. The rotor 7 has an upstream portion 70 on the upstreamside and a downstream portion 71 on the downstream side and agitatingmembers 7 a provided on the outer peripheries of the upstream portion 70and of the downstream portion 71 are tilted. The tilt is set in such away that a bottom portion 7A of a substantially linear portion of theagitating member 7 a advances more in the rotational direction of therotor 7 than a top portion 7B. A rotation from the motor is transmittedvia a belt 8 and a rotating shaft 9 so as to rotate the rotor 7.

Reference numeral 10 in FIG. 1 denotes a water supply passage providedon the sealed casing 1 in such a way that a water spouting port 10 aopposes a top end face 7T (more preferably, in such a away that thewater spouting port 10 a opposes the center of the top end face 7T ofthe rotor 7).

Thus, when a paper-making material is supplied into the sealed casing 1from the paper-making material supply passage 3 and a rotation of amotor (not shown) is transmitted through the belt 8 and the rotatingshaft 9 so at to rotate the rotor 7, foreign matter in the paper-makingmaterial cannot pass through the screen 2 and is deposited within thefirst chamber 1A. The paper-making material which passes through thescreen 2 is guided into the sealed casing 1 through the second chamber1B and the refined paper-making material discharge passage 4.

The flow of paper-making material proceeding downstream is hampered bydiluted water supplied from the diluted water introduction port R1midway on the screen 2, thereby enhancing the capacity of the screenapparatus for separating foreign matter in the paper-making materialfrom fibers of an acceptable quality. Further, paper-making materialpasses through the screen 2 upstream so that paper-making material whosedensity has been intensified is diluted by diluted water so as tointensify the effects of separating fibers of an acceptable quality.Further, pieces that have not yet melted and that are contained in thepaper-making material collide with the convex portions RT provided onthe side facing the rotor 7 of the ring portion R are forced backupstream of the paper-making material, thus enhancing the effects ofseparating foreign matter from fibers of an acceptable quality in thepaper-making material.

Because the water spouting port 10 a of the first water supply passage10 provided on the sealed casing 1 opposes the top end face 7T of therotor 7 downstream of the screen 2 within the first chamber 1A, watercolliding with the center of the top end face 7T of the rotor 7 flows ina substantially horizontal direction so as to hamper the flow of thepaper-making material proceeding toward the foreign matter dischargeport 1 c from the opening portion 2A above the screen 2. In other words,this action forces back upstream of the first chamber 1A fibers, whichwere flowing out to the foreign matter discharge port 1 c by rejectsealing, thereby enhancing the capacity of the screen apparatus forseparating foreign matter from fibers of an acceptable quality in thepaper-making material.

The foreign matter discharge passage 5 and the heavy foreign matterdischarge passage 6 are appropriately adjusted in degrees of opening, orare opened or closed, by valves (not shown) for opening and closing thepassages so as to guide foreign matter deposited within the firstchamber 1A out of the sealed casing 1.

Although according to the above-described embodiment, an end portion ofthe lower portion 7A of the agitating member 7 a on the downstream sideis extended up to a position opposing the diluted water introductionport R1 (see FIG. 1), the present invention need not restricted and, asshown in FIG. 6, it is permissible to eliminate the portion of theagitating member 7 a that opposes the diluted water introduction portR1.

Although the top end face 7T of the rotor 7 is formed on a flat surface(see FIG. 1), the present invention need not be restricted to thisexample, and it is permissible to provide projections (scraping blades)7 z, as shown in FIGS. 6-8, and change the flow direction of water fromthe water spouting port 10 a to a horizontal direction with the use ofcentrifugal force by the projections (scraping blades) 7Z, therebyintensifying the effects of reject sealing described above. Further, thearrow shown in FIG. 7 indicates the rotational direction of the rotor 7.

It is permissible to provide a guide G for guiding water from the waterspouting port 10 a around the water spouting port 10 a so as to guidewater from the water spouting port 10 a to the vicinity of theprojections (scraping blades) 7Z so that the face of the guide G opposesthe top end face 7T of the rotor 7.

Although an opening width W in the circumferential direction of the ringportion R of the concave portion R0 shown in FIG. 5 is set so as to beless than the length L of the flat face in the circumferential directionof the ring portion R of the convex portion RT, the present invention isnot restricted to this example. As shown in FIG. 10, the opening width Win the circumferential direction of the ring portion R of the concaveportion R0 may also be set so as to be greater than the length L of theflat face in the circumferential direction of the ring portion R of theconvex portion RT.

Although in the embodiments described above the convex portion RT isprovided so as to project from the face of the screen 2 to the sidefacing the rotor 7 of the ring portion R, the present invention need notbe restricted to this example. As shown in FIGS. 11, 12, the convexportion RT of the uneven face may also be provided on the side facingthe rotor 7 of the ring portion R in such a way that it does not projectfrom the inside wall face of the screen 2. Because the type shown inFIGS. 11, 12 is the same as the one described in FIGS. 3-5, except thatthe convex portion RT is not projected from the face (inside wall) ofthe screen 2, identical reference numerals have been attached to thesame components as those described in FIGS. 3-5, and a descriptionthereof has accordingly partly omitted.

In other words, the convex portion RT has a front end portion X of theuneven portion and a rear end portion Y which relative to the verticaldirection of the casing 1 is positioned at a position lower than thefront end portion X of the convex portion RT and is tilted in such a waythat relative to the rotational direction of the rotor 7 (see thedirection of an arrow shown in FIG. 12( b)) the front end portion X ofthe convex portion RT is nearer than the rear end portion Y of theconvex portion RT.

Further, a concave portion RO is located between adjoining convexportions RT and a plurality of each of the convex portions RT and of theconcave portions RO are provided on the ring portion R.

The convex portion RT described in FIGS. 11, 12 can enhance the capacityof the screen apparatus for separating foreign matter from fibers of anacceptable quality in paper-making material like the convex portion RTdescribed in FIGS. 3-5, because pieces that have not yet melted and thatare in the paper-making material collide with the convex portion RT arenot only separated but also brought back upstream of the paper-makingmaterial.

1. A screen apparatus comprising: a sealed casing having a paper-makingmaterial supply port, a refined paper-making material discharge portpositioned above the paper-making material supply port and a foreignmatter discharge port positioned above the refined paper-making materialdischarge port; a screen for dividing the interior of the sealed casinginto a first chamber and a second chamber and for separating foreignmatter existing in the paper-making material, the screen being of acylindrical shape and with end portions that are both open, the screenhaving circular holes or slit-like openings on a side face thereof andstood within the sealed casing in such a way that a direction of heightthereof faces a vertical direction, both open end portions of the screenhaving an upper opening portion and a lower opening portion with theupper opening portion positioned below the foreign matter discharge portand the lower opening portion positioned above the paper-making materialsupply port; a paper-making material supply passage connected to thepaper-making material supply port in order to supply paper-makingmaterial to a first chamber from a downward direction; a rotor disposedinside the screen within the first chamber and having an agitatingmember for agitating the paper-making material within the sealed casing;a refined paper-making material discharge passage connected to therefined paper-making material discharge port and also connected to thesecond chamber so as to guide paper-making material that has beenrefined out of the sealed casing via the screen; a foreign matterdischarge passage connected to the foreign matter discharge port andalso connected to the first chamber so as to guide out of the sealedcasing foreign matter existing in the paper-making material and whichdoes not pass through the screen; and a water supply passage mountedonto the sealed casing so that a water spouting port opposes the top endface of the rotor.
 2. The screen apparatus according to claim 1 furthercomprising: a ring portion provided at a midway position on the screen,the screen being divided by the ring portion into an upstream screenportion and a downstream screen portion, the ring portion being providedwith a diluted water introduction port for introducing diluted waterinto the first chamber; a diluted water passage provided via the sealedcasing and connected to the diluted water introduction port; and anuneven portion provided on a side opposing a rotor of the ring portion,wherein a convex portion of the uneven portion is provided so as toproject from an inside wall face of the screen, and the uneven portionhas a front end portion of the convex portion and a rear end portion ofthe convex portion that relative to a vertical direction of the casingis positioned lower than the front end portion of the convex portion,and which front end portion is tilted in such a way that relative to arotational direction of the rotor the front end portion of the convexportion is nearer the rear end portion of the convex portion.
 3. Thescreen apparatus according to claim 1 further comprising: a ring portionprovided at a midway position on the screen, the screen being divided bythe ring portion into an upstream screen portion and a downstream sidescreen portion, the ring portion being provided with a diluted waterintroduction port for introducing diluted water into the first chamber;a diluted water passage provided via the sealed casing and connected toa diluted water introduction port; and an uneven portion provided on aside opposing a rotor of the ring portion, wherein a convex portion ofthe uneven portion is provided not to project from an inside wall faceof the screen and the uneven portion has a front end portion of theconvex portion and a rear end portion of the convex portion thatrelative to a vertical direction of the casing is positioned lower thanthe front end portion of the convex portion, and which front end portionis tilted in such a way that relative to a rotational direction of therotor the front end portion of the convex portion is located nearer thanthe rear end portion of the convex portion.